Just check to make sure you have enough depth so the subs fit physically and you should be fine. Those Sundown subs move a lot of air so you'll likely need a 3" port per sub which is tricky but not impossible. I did it before so I know with effort it can work. It will likely be easier in your case since you will only have one motor structure to miss with the ports.

Search "Tacoma Audio Endeavor" using my name as the poster in the search. You should find the thread. It's not exactly a how to but it's close. There's a lot of work that goes into doing the bottom portion to prepare the area. After that though, you can just throw a new top on it whenever. Just cut a new one.

Can't post pics because I am in Atlanta and not home, but I am the one who put the two Alpine Type R (8 inch) in the Tacoma. The 2 8s are more than enough.

With my setup, I did not have to install any ports. 10s will not fit down there. For peace of mind, I created a rubber bumper for where the seat contacts the metal. It never touched the speaker, but I did this for extra peace of mind.

Not sure what speakers you'll use in the end, but I did not use any filler, I simply used some sound deadener in every surface.

Which set up do you think would be louder two Sundown SD-2 10's or four 8's? Which would have the best SQ?

The 10's will be in a sealed box behind my seat and it will be a two chamber box with about 0.8 cubic feet per chamber, and the 8's can be in that box or under my seat which will have about 1 cubic foot and will be sealed.